Tag Archives: 10GbE switch

Deploying 10G ToR/Leaf Switch for Different Size Networks

With the migration from Gigabit Ethernet to 10 Gigabit Ethernet, cabling and network switching architectures have been reevaluated to guarantee a cost-effective and smooth transition. 10Gb ToR (Top of Rack) or leaf switch has evolved with significant performance gains and cost-per-port reduction. This post will introduce the benefits of ToR architecture and explains how to deploy 10G ToR/leaf switch for different size networks.

Why Use Top-of-Rack Architecture

ToR or leaf-spine is a network architecture design where there are only two tiers of switches between the servers and the core network. In ToR network design, a feature-rich 10GbE switch handles Layer2 and Layer3 processing, data bridging and Fibre Channel over Ethernet (FCoE) for an entire rack of servers. This approach contributes to an agile infrastructure because the ToR/leaf switches can support multiple I/O interfaces, including GbE, 10GbE and 40GbE. The 10G ToR/leaf switches utilized in the ToR architecture usually come with the advantage of low power consumption, ease of scale and simplified cabling complexity. When acting as a ToR/leaf switch, each 10G Ethernet switch can be placed just one hop away from another, no need to jump up and down in the tree design, enabling improved latency and bottlenecks. With a ToR design, you can eliminate cabling nightmares, minimize bottlenecks while building a network foundation for mission-critical applications that also provides a clear path for future growth.

Top of Rack Architecture

Campus Network Applications

For campus networks applications, the 10GE switches work as aggregation or core switches in the ToR network architecture. Here we take FS S5850-48S6Q 10G ToR/leaf switch as an example to illustrate how to build a ToR network in campus networks. In the following application diagram, two FS S5850-48S6Q 10GE switches are utilized as aggregation switches as the bridge to build connections between 40G switches in the core network and gigabit switches in the access layer.

10G ToR Switch Campus Network Application

SMB (Small and Medium-Sized Business) Applications

For small and medium-sized businesses, ToR network architectures are becoming more preferable by IT managers than ever before. Because ToR architectures enable them to implement a single cabling model that can support Gigabit Ethernet and 10 Gigabit Ethernet and unified network fabric today, while supporting future 40 and 100 Gigabit Ethernet standards as they come to market. Using ToR architecture for fiber cable management, business IT managers have the flexibility to deploy preconfigured racks with different connectivity requirements in any rack position. For example, a rack of servers running multiple Gigabit Ethernet connections can be placed next to a rack of servers with 10 Gigabit Ethernet and FCoE connections to each server.

Data Center Applications

In hyper-scale data centers, there might be hundreds or thousands of servers that are connected to a network. In this case, ToR/leaf switches work in conjunction with spine switches in data centers to aggregate traffic from server nodes and then connect to the core of the network. Now given that we need to build a data center fabric with a primary goal of having at least 480 10G servers in the fabric. In this case, we can use FS S8050-20Q4C as spine switch and S5850-32S2Q as ToR/leaf switch. As shown in the figure below, the connections between spine switches (FS S8050-20Q4C) and ToR/leaf switches (FS S5850-32S2Q) are 40G, while connections between the leaf switches and servers are 10G. The port numbers on each spine switch determines the number of leaf switches we can use. But the maximum amount of 10G servers we can connect to ToR/leaf switch here is 24 because the ratio of reasonable bandwidth between leaf and spine switch cannot exceed 3:1. Thus the total amount of bandwidths we can get here is 480x10G.

10G ToR Switch Data Center Application

Top-of-Rack Cabling Recommendations

ToR network architectures utilize available cabling media options with flexibility at the rack level, using various server patch cable types, while taking advantage of fiber uplinks from the rack for horizontal cabling. Investment in the cabling media for 10, 40, and 100 Gigabit Ethernet connectivity involves striking a balance among bandwidth, flexibility, and scalability. Although both fiber and copper can support 10G, 40G and 100G transmission, fiber is the recommended horizontal cabling media as it offers an optimal solution for high speed 40G and 100G transmission over relatively long distances. Note that 40G and 100G transmission calls for multiple fiber strands (OM3, OM4, and SMF fiber).

Conclusion

The choice of ToR networking architecture can substantially affect throughput, sustainability, optimum density and energy management. As the key element of building ToR networks, 10G ToR/leaf switch can help you scale up networking architecture while delivering low-latency and high-bandwidth links. FS S5850/N5850 series switches are high performance 10GbE ToR/leaf switches which can work with Broadcom, Cisco, Juniper, Arista switches, as well as other major brands. For more information about 10GbE ToR/leaf switches, please kindly visit www.fs.com.

Related Article: 10G ToR/Leaf Ethernet Switch: What Is the Right Choice?

What Is a Core Switch and Why Do We Need It?

Network switches are categorized into different types according to different principles, such as fixed switch and modular switch based if you can add expansion module to it, and managed switch, smart switch and unmanaged/dumb switch depending on whether you can configure it and the complexity of the configuration. Another way to classify the type of a network switch is by the role it plays in a local area network (LAN). In this case, one switch is considered to be an access switch, an aggregation/distribution switch or a core switch. In small networks we do not see core switch. So many people are having questions about what core switches are. Do you know what is core switch? Is there only one core switch in a network? What are the differences between core switch and aggregation/access switch?

What Is Core Switch?

If we spend some time looking up dictionaries for the meaning of core switch, we will find a definition similar to “A core switch is a high-capacity switch generally positioned within the backbone or physical core of a network. Core switches serve as the gateway to a wide area network (WAN) or the Internet—they provide the final aggregation point for the network and allow multiple aggregation modules to work together (An excerpt from Techpedia).” The definition explains its high-capacity feature, the physical location and its function of connecting multiple aggregation devices in network.

What Are the Differences Between Core Switch and Other Switches?

The biggest difference between core switch and other switches is that, core switch is required to always be fast, highly available and fault tolerant since it connects all the aggregation switches. Therefore, a core switch should be a fully-managed switch. But if it is a switch not used in the core layer, it can be a smart switch or an unmanaged switch.

Another difference is that, the core switch is not always needed in a LAN while we may often have the aggregation switch and the access switch. Because in small networks that have only a couple of servers and a few clients, there’s no actual demand for a core switch vs aggregation switch. In the scenario where we don’t need the core layer, we often call it a collapsed core or collapsed backbone since the core layer and the aggregation layer are combined.

The third difference is that there’s generally only one (or two for redundancy) core switch used in a small/midsize network, but the aggregation layer and the access layer might have multiple switches. The figure below shows where the core switch locates in a network.

Core switch in the core layer

What Should Be Kept in Mind When Using Core Switch?

The first thing we should keep in mind is that core switch is urgently required in two occasions. One occasion is when the access switches are located in different places and there is a aggregation switch in each place, then we need a core switch to optimize the network. Another occasion is when the number of the access switches connecting to a single aggregation switch exceeds the performance of it, and we need to use multiple aggregation switches in a single location, then the use of core switch can reduce the complexity of the network.

With core switch and without core switch

As for specific type and number of core switch that we should adopt in a network, that depends on the scale and budget of our network, including how many servers, clients or lower layers switches we have. For example, say that a small network has 100 users and has 6 48-port Gigabit aggregation switches, a suitable core switch will be like Juniper EX2200, Cisco SG300, or FS.COM S5800-8TF12S 10GbE switch.

The second thing is that a core switch should be fully-managed, which means it should support different method of management, such as web-based management, command line interface and SNMP management. Also it should have some advanced features like support for IPv6, built-in Quality of Service (QoS) controls, Access Control Lists (ACLs) for network security.

And generally the connections to the core layer should be the highest possible bandwidth. In addition, since the core switch act as the center of a LAN, it should be able to reach any devices in the network, not directly but within the routing table. A core switch is usually connected to the WAN router.

Conclusion

In the design of a network, there might be access layer, aggregation layer and core layer. Though the core layer is not required in smaller networks, it is indispensable in medium/large networks. And the high-capacity core switch plays an important role in delivering frames/packets as fast as possible in the center of the network. Its contribution can not be underestimated especially in networks where speed, scalability and reliability are key to users.

Related Article: 48-Port 10GE Switch Selection: What Is the Right Choice?
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